NOAA Scientists Discover Novel Way to Detect Low Level Exposure to Seafood Toxin: Students at Northwest Indian College Learn the Ropes

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Narration: With Green Acre Radio this is Martha Baskin. Scientists have long known a toxin produced by harmful algal blooms moves through the food web and has serious impacts on humans and marine mammals. The first documented case of amnesic shellfish poisoning occurred in Eastern Canada in 1987 when over a hundred people became ill from contaminated mussels. Since then consistent monitoring of shellfish beds for the harmful marine toxin, domoic acid, has been effective in protecting human consumers. “WHAT WE’RE CONCERNED ABOUT ARE WHAT ARE THE IMPACTS OF LOW LEVEL EXPOSURE. SO BELOW THOSE REGULATORY LIMITS.” NOAA fisheries biologist, Kathi Lefebvre, is the lead researcher in a new study that’s uncovered a  novel way to detect low-level chronic exposure to seafood toxins in marine mammals. The discovery has potential human health benefits. “THAT’S PROBABLY NOT A BIG DEAL FOR CONSUMING JUST A FEW TIMES. BUT THERE ARE COMMUNITIES THAT SUBSISTENCE HARVEST SHELLFISH AND EAT THEM ON A DAILY BASIS THROUGHOUT THEIR LIFE SO THAT’S WHAT WE’RE CONCERNED ABOUT.” Not just for domoic acid, but all kinds of toxins, says Lefebvre.

Up until now, the absence of a biological marker for chronic exposure has been a barrier to accurately assess possible effects. This is where zebrafish come in. Most often associated with household aquariums, scientists injected the fish with low levels of domoic acid two to four times a month over nine months. “REALLY WHAT WE’RE DOING WITH ZEBRA FISH IS WE’RE JUST USING THE BIOLOGICAL MACHINERY OF A LIVING ORGANISM, A LIVING VERTEBRATE. A LOT OF PROCESSES INVOLVED IN LIFE ARE CONSERVED ACROSS SPECIES.” Genes that regulate various body functions often follow the same pathway in humans as they do in zebrafish. When Lefebvre and her team looked at gene expression, they found a significant immune response. “THEN WE LOOKED IN THE BLOOD AND WE FOUND AN ANTIBODY TO DOMOIC ACID. SO WHAT THAT MEANS IS THE FISH ARE PRODUCING AN ANTIBODY RESPONSE AGAINST THE DOMOIC ACID AND THAT ANTIBODY IS DETECTABLE IN THE BLOOD.” But they didn’t stop there. The NOAA scientists tested their findings with colleagues at the Marine Mammal Center in Sausalito who’ve identified two syndromes of domoic acid in California sea lions, acute and chronic. Sea lions consume massive quantities of anchovies resulting in seizures or death of hundreds of animals yearly. 

What the exact findings mean for humans, especially coastal and native communities, who subsistence harvest shellfish has yet to be uncovered. Kathi Lefebvre says her dream is to develop a diagnostic test, a kit, to monitor low level domoic acid exposure. “CHRONIC HEALTH ISSUES SEEM TO BE PLAGUING OUR SOCIETY. WE HAVE FIBROMALAGIA, WE HAVE THIS WE HAVE THAT AND I WILL TELL YOU MY BELIEF IS THAT ALL OF THESE CONDITIONS ARE A RESULT OF OUT CONTINUED LOW LEVEL EXPOSURE TO ALL KINDS OF TOXINS IN THE ENVIRONMENT.”  But until such a test is developed, or magic elixir found to cleanse toxins from oceans and rivers everywhere, Lefebre and her team are bringing their findings to tribal communities. Students and instructors at the Northwest Indian College on the Lummi Reservation are the first to learn how to detect domoic acid. NOAA biologist Elizabeth Frame. “IN THIS LAB WE’RE GOING TO SHOW YOU HOW TO GET DOMOIC ACID FROM YOUR SOLID MUSCLE TISSUE OR CLAM TISSUE INTO A LIQUID FORM THAT WE CAN INJECT INTO THE HPLC.” That’s the high performance liquid chromatography machine. It separates molecules based on size and charge, in this case, molecules from local clams and Dungeness crabs. Students dissect tissue, add methanol and water, homogenize the samples and transfer them to a centrifuge. “ONE THING YOU WANT TO BE SURE THIS PART HERE THAT ACTUALLY GRINDS AND CUTS, WE WANT THAT DOWN HERE AND WE TURN IT ON AND THERE’S THIS NICE LITTLE GRINDING NOISE.” // Student Josie Kamkoff is doing her thesis on the absence or presence of domoic acid in clams. “I CHOSE HEART COCKLE CLAMS BECAUSE THEY ARE ONLY HARVESTED FOR SUBSISTENCE. SO THE PEOPLE THAT EAT HEART COCKLE CLAMS LOCALLY THEY KIND OF DON’T HAVE MUCH DEFENSE FOR THESE KINDS OF THINGS.” Kamkoff identifies herself as Upik Eskimo and Lummi Indian. She says her people have known for hundreds of years not to harvest during seasonal or periodic harmful algal blooms, but dealing with chronic algal toxin exposure that moves up the food chain is different. Is it important enough for her to want to study further? “I THINK ITS VERY IMPORTANT BECAUSE THIS IS WHAT OUR ENVIRONMENT IS MADE TO PRODUCE AS A FOOD.” The results of the lab experiment conducted with NOAA scientists at the Northwest Indian College showed no indication of domoic acid in the local clams and a low concentration in Dungeness crab.